The present invention relates to the cleaning of residues from surfaces in a substrate processing chamber.
In the fabrication of electronic circuits and displays, semiconductor, dielectric, and conductor materials, such as for example, polysilicon, silicon dioxide, aluminum or tungsten silicide, are formed on a substrate by, for example, chemical vapor deposition (CVD), physical vapor deposition (PVD), oxidation and nitridation processes. In CVD processes, a reactive gas is used to deposit material on the substrate, and in PVD processes, a target is sputtered to deposit material on the substrate. In oxidation and nitridation processes, an oxide or nitride material, for example, silicon dioxide or silicon nitride, respectively, is formed on the substrate by exposing the substrate to a suitable gaseous environment. In subsequent processes, a patterned mask of photoresist or hard mask is formed on the substrate by photolithographic methods, and the exposed portions of the substrate are etched by an energized gas to form patterns of gates, vias, contact holes or interconnect lines.
In such processes, process residues may deposit on the surfaces of walls and other components in the chamber. The composition of the process residues may depend upon the composition of the process gas, the material being deposited or etched, and the composition of material on the substrate. These residues are periodically cleaned off the chamber surfaces to reduce or prevent contamination of the substrate. The chamber may be cleaned by a wet-cleaning process in which the chamber is shut down and an operator scrubs or wipes the chamber walls with an acid or solvent. The chamber may also be cleaned by a dry-cleaning process in which plasma or microwave-activated cleaning gas is provided in the chamber. However, some cleaning processes are slow at cleaning certain types of process residues, for example, residues which are relatively thick or which may have a chemical composition that is hard to clean. In addition, the cleaning processes can leave behind other residues, for example, that may be generated by the adsorption of the cleaning gas onto the chamber surfaces. For example, when the cleaning gases comprises fluorine-containing species, such as a CF4 or NF3 gas, the fluorine-containing species may be adsorbed onto the chamber surfaces. These adsorbed species can react can adversely affect the quality of subsequent processes performed in the chamber.
Thus, it is desirable to effectively clean residues formed on surfaces in a substrate processing chamber. It is further desirable to have a cleaning process which does not require shutting down of the chamber. It is further desirable to be able to remove residues that are left behind or generated by the cleaning processes itself.
A method of cleaning residues on surfaces in a chamber having process electrodes, the method comprising:
(a) placing in the chamber, a sacrificial substrate comprising a sacrificial material;
(b) introducing a sputtering gas into the chamber; and
(c) energizing the sputtering gas by applying a voltage to the process electrodes at a power level of at least about 500 watts to sputter sacrificial material from the substrate that reacts with and cleans the residues on the surfaces in the chamber.
A substrate processing chamber comprising:
a substrate transport capable of transporting a sacrificial substrate into the chamber, the sacrificial substrate comprising a sacrificial material;
a gas supply capable of providing a sputtering gas in the chamber;
a plasma generator comprising process electrodes that are capable of energizing the sputtering gas;
an exhaust capable of exhausting the sputtering gas; and
a controller adapted to control the substrate transport, gas supply, plasma generator, and exhaust, to:
(i) transport a sacrificial substrate into the chamber,
(ii) provide a sputtering gas in the chamber, and
(iii) energize the sputtering gas by controlling the plasma generator to apply a biasing voltage to the process electrodes at a power level of at least about 500 watts to sputter sacrificial material from the substrate to clean process residues from surfaces in the chamber.
A method of processing substrates in a chamber having process electrodes, the method comprising:
(a) processing one or more production substrates in the chamber by providing a substrate in the chamber, introducing a process gas in the chamber, and energizing the process gas, thereby forming process residues on the surfaces in the chamber;
(b) cleaning the process residues from the surfaces in the chamber by providing in the chamber, an energized cleaning gas comprising fluorine-containing species to clean the process residues, whereby cleaning residues comprising fluorine-containing species are formed on the surfaces in the chamber; and
(c) cleaning the cleaning residues by transporting into the chamber, a substrate comprising a silicon-containing material, introducing a sputtering gas into the chamber, and energizing the sputtering gas to sputter silicon-containing material from the substrate that is capable of reacting with the cleaning residues comprising the fluorine-containing species to form volatile compounds.
A substrate processing chamber comprising:
a substrate transport capable of transporting a substrate into the chamber;
a gas supply capable of providing a gas in the chamber;
a plasma generator comprising process electrodes capable of energizing the gas;
an exhaust capable of exhausting the gas; and
a controller adapted to control the substrate transport, gas supply, plasma generator, and exhaust, to:
(i) process one or more production substrates in the chamber by transporting the production substrates into the chamber, providing a process gas in the chamber, and energizing the process gas, thereby forming process residues on surfaces in the chamber,
(ii) clean the process residues from the surfaces in the chamber by providing in the chamber, an energized cleaning gas comprising fluorine-containing species that cleans the process residues, whereby cleaning residues comprising fluorine-containing species are formed on the surfaces in the chamber; and
(iii) clean the cleaning residues by transporting into the chamber, a substrate comprising a silicon-containing material, introducing a sputtering gas into the chamber, and energizing the sputtering gas to sputter silicon-containing material from the substrate that is capable of reacting with the cleaning residues comprising the fluorine-containing species to form volatile compounds.